The invention relates to lighting devices and, more particularly, to light fixtures, light bulbs, lamps or the like that use solid state lighting sources, such as light emitting diodes (LEDs).
LED lighting systems have advantages over traditional lighting solutions such as incandescent and fluorescent lighting because they use less energy, are more durable, operate longer, can be combined in multi-color arrays that can be controlled to deliver virtually any color light, and contain no lead or mercury. In many applications, one or more LED dies (or chips) are mounted within an LED package or on an LED module, which may make up part of a lighting system, a light fixture, lighting unit, lamp, light bulb or the like which includes one or more drivers or power supplies to power the LEDs. The LEDs can be controlled to set and adjust brightness and dimming levels.
Light of different color hues, or different correlated color temperature (CCT), can be created by combining LEDs with different emission color points. The LEDs with different emission color points can be selectively combined to create virtually any color light. Typically, the lighting system is designed so that each color light source can be managed separately based on the drive current characteristics for that color. The driver is designed to match the configuration of LEDs in the lighting system so that control can be accomplished by using separate color control channels. With such an arrangement, a desired CCT can be maintained at any dimming level or user-configurable CCT can be provided. As one example, an LED lamp can be dimmed following the profile of color vs. brightness exhibited by incandescent lamps.